Tying lists to other node types

I have not been following the project from it's beginning, so this question might already have been answered before, but why og lists are tied to the forums? Can it be a configuration setting allowing to tie the lists with other node types as well? What is the main difference between forums and other node types? Forums have predefined containers or topics, but otherwise they are similar to blogs or stories.

Most sites are configured to let authenticated users posting their blogs, not forum posts. If a list would be tied with a blog post, then each new incoming mail becomes a blog post in that group and replies become comments. This way people could participate in site's 'life' without ever opening their browser.